KR20000068198A - Thermoplastic Compositions Including Zinc Oxide and Tetrafluoroethylene Homo or Copolymers and Shaped Articles Prepared Therefrom - Google Patents

Abstract

A molded article having improved abrasion properties is provided by a polymerizable composition in which polymers and copolymers of zinc oxide and tetrafluoroethylene having a selected size and molecular weight are uniformly dispersed in controlled amounts.

Description

Thermoplastic Compositions Including Zinc Oxide and Tetrafluoroethylene Homo or Copolymers and Shaped Articles Prepared Therefrom}

Certain single thermoplastic polymers and blends of these polymers with other polymers such as polyimide and polyimide precursor materials are injection moldable and provide uniquely combined properties. Due to the excellent performance properties of these polymers under stress, they are bushings, seals, compressor blades and impellers, piston and piston rings, gears, thread guides, cams, and brake linings. , And clutch face forms.

Various additives have been included in this composition. Graphite has been incorporated in bearing applications to improve wear characteristics. Fluoropolymers have been incorporated for gamma power. Unfortunately, there has been a continuous problem of obtaining a uniform distribution of additives in such molding compositions. As a result, a large amount of expensive additives have been required to provide satisfactory properties to the molded article. These compositions have been used in a limited way due to the high cost of containing a large amount of expensive components such as polytetrafluoroethylene as well as regeneration of the components for wear and support materials.

<Summary of invention>

The present invention provides a polymerizable composition in which a copolymer of zinc oxide, an unfibrillated tetrafluoroethylene homopolymer and tetrafluoroethylene (collectively referred to herein as PTFE) has a controlled amount uniformly dispersed in micronized form. One problem is to be solved. Zinc oxide should be of selected particle size and PTFE should have a controlled molecular weight. The two components are present in the composition in the selected weight ratio. When used according to the invention these additives are uniformly dispersed throughout the polymer matrix and a molding composition with exceptional uniformity is obtained. Molded articles made therefrom exhibit improved wear characteristics.

The polymerizable blends of the present invention have about 40 to 98 weight percent of at least one thermoplastic polymer that is melt processable at temperatures below about 400 ° C., an average particle size of less than 3.7 μm, preferably at least 25% of which have a particle size of less than 2 μ From about 1 to 38 weight percent zinc oxide and from about 38 to 1 weight percent PTFE in the form of micronized powder having a molecular weight ranging from about 80,000 to 1,000,000. PTFE has an average particle size of about 1.8 μm to about 150 μm. Preferably the size is 4-20 μm. Zinc oxide and PTFE particles are present in a ratio of about 95 parts PTFE / 5 parts zinc oxide to about 10 parts PTFE / 90 parts zinc oxide. By adjusting the composition components described above, it was found that the components were blended in a commercial device such as a screw extruder to obtain a blend with exceptional uniformity. It is believed that a synergistic effect is seen in providing composition uniformity when the additive is used as described herein. Improved results are not observed when used individually.

High performance sex products are formed by suitable molding operations such as injection or compression molding from the polymerizable composition of the present invention. The addition of zinc oxide to thermoplastic resins comprising PTFE in accordance with the present invention improves the wear and reproducibility of the article, which is a support material. The potential range of action of these wear and friction materials is also improved. Another advantage is the potential cost reduction as less expensive PTFE is required.

The compositions of the present invention may also consist of blends of thermoplastic polymers with other polymers such as polyimide and polyimide precursor resins. This blend may comprise about 40 to 93 weight percent thermoplastic polymer and about 5 to 40 weight percent polyimide or polyimide precursor resin, preferably 10 to 30 weight percent of polyimide or polyimide precursor resin do. The polyimide may or may not be melt processable.

1 is a micrograph of Sample VI described in Example 3, which is a polymerizable composition not within the scope of the present invention, showing inferior PTFE dispersion in the sample.

2 is a micrograph of Sample VIII described in Example 3, the polymerizable composition of the present invention, showing that the PTFE dispersion in the sample is substantially uniform.

Polypropylene, polyethylene, chlorinated polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyamide, polysulfone, polyetherimide, polyether sulfone, polyphenylene sulfone, polyphenylene sulfide, polyether ketone, polyether ether Ketones, ABS resins, polybutadiene, polymethyl methacrylate, polyacrylonitrile, polyacetals, polycarbonates, ethylene-vinyl acetate copolymers, polyvinyl acetates, ethylene-vinyl acetates, ethylene-tetrafluoroethylene aerials A wide range of melt processable polymers can be blended with zinc oxide and PTFE particles, such as copolymers, aromatic polyesters, grafted polyphenylene ether resins, and individual resins in liquid crystal polymers or mixtures of various types of alloys or plural resins. Polyamides that may be used include nylon 6, nylon 6,6, nylon 610, nylon 612 and aromatic polyamides. Polyesters include polybutylene terephthalate and polyethylene terephthalate.

The melt processable polyester is preferably in the form of a liquid crystalline polymer (LCP). LCPs are generally polyesters, examples of which include, but are not limited to, polyesteramides and polyesterimides. LCP is described in U. S. Patent Nos. 4,169,933, 4,242,496, and 4,238,600 to Jackson et al. Others are described in US Pat. No. 4,219,461 to Kahlundan, particularly preferred LCPs are phenyl hydroquinone, hydroquinone, t-butyl hydroquinone, 1,4-benzene dicarboxylic acid, 1,3 Prepared by changing the ratio from monomers such as -benzene dicarboxylic acid, 4-hydroxybenzoic acid, terephthalic acid and 2,6-naphthalene dicarboxylic acid Preferred LCP compositions are described in US Pat. No. 4,664,972, incorporated herein by reference. And 5,110,896. The composition of the patent document referred to initially consists essentially of (I) 95 to 55 mol% of butylhydroquinone and 5 to 45 mol% of at least one polyaromatic diol. Dicarboxylic acid components selected from aromatic diols, (II) "para" or "meta" oriented aromatic dicarboxylic acids or 1,4-cyclohexane dicarboxylic acids or mixtures thereof, provided that 80 of the dicarboxylic acid components Up to mole% comprises naphthalene dicarboxylic acid), and (III) an aromatic hydroxycarboxylic acid component selected from 4- (4 "-hydroxyphenyl) benzoic acid or mixtures thereof, said copolyester Contains components (I) and (II) in the same chemical equivalent and comprises about 20 to 60 mole percent of component (III) based on the total moles of (I) + (II) + (III). The composition of the second-referenced patent document consists essentially of (I) hydroquinone, (II) 4,4'-dihydroxyphenyl, (III) terephthalic acid, (IV) 2,6-naphthalene dicarboxylic acid and (V) Consisting of repeating units derived from 4-hydroxybenzoic acid, wherein the molar ratio of (I) :( II) is 65: 35-40: 60, preferably 60: 40-40: 60, and (III) :( IV Molar ratio of 85:15 to 50:50, preferably 85:15 to 60:40, and the molar ratio of (I) :( II) to the sum of (III) :( IV) is substantially 1: 1, preferably 0.95-1.05: 1.00, and (V) is present at 200 to 600, preferably 200 to 450 moles per 100 moles of (I) + (II). Other LCPs useful in this invention are essentially repeat units derived from (I) t-butylhydroquinone and terephthalic acid, (II) t-butylhydroquinone and 2,6-naphthalene carboxylic acid, and (III) 4-hydroxybenzoic acid. Wherein the molar ratio of (I) :( II) is about 4: 1 to about 1: 4, more preferably about 3: 1 to 1: 3, and (I) + (II) :( III) is From about 3: 1 to about 2: 3.

A wide range of polyimide resins can be used in the present invention. Aromatic polyimides can be used, such as those disclosed in US Pat. No. 3,179,614 to Edwards and US Pat. No. 4,755,555 to Manwiller and Anton. It has been found that such specific, i.e., polyimide having a rigid polymerization structure is particularly satisfactory in the present invention. Representative of such hard polymerizable materials include m-phenylene diamine (MPD); Bis-4,4 '(3 aminophenoxy) biphenyl; 3,4-oxydianiline (3,4-ODA); Oxydianiline (ODA); p-phenylene diamine (PPD); Benzophenone-3,3 ', 4,4'-tetracarboxylic dianhydride (BTDA); Bis phenol-A-diphthalic anhydride (BPADA); Pyromellitic dianhydride (PMDA); And aromatic diamines and anhydrides such as 3,3 ', 4,4'-biphenyltetracarbocyclic dianhydride (BPDA). The dianhydride and the aromatic diamine can be reacted in substantial equimolar amounts. However, excess dianhydride or diamine may be used to advantageously modify the final polyimide properties. Reaction products of dianhydrides and aromatic diamines are polyimide precursor resins comprising polyamic acid, which can be thermally or chemically converted to polyimides according to known techniques. Recently, U.S. Patent No. 5,346,969 to Kaku discloses polyimide precursor resins, such as those described in U.S. Pat. Blends in the form of crystalline polymers (LCPs) are described. A blend of a polyimide precursor and at least one polymer that is melt processable at temperatures below about 400 ° C. is combined to obtain a polyimide having injection molding capability. At least one polymer that is melt processable at temperatures below about 400 ° C. is blended with the polyimide resin. The term "melt processability" is used in the conventional sense that the polymer can be processed in an extrusion apparatus at a specified temperature without substantial degradation of the polymer. Zinc oxide and PTFE particles are included in the blending action.

Zinc oxide particles can be produced by differentiating and sieving this oxide so that the required particle size distribution can be obtained from commercially available crystalline zinc oxide.

Cofibrils such as unfibrillated tetrafluoroethylene polymers and tetrafluoroethylene / hexafluoropropylene are commercially available in micropowder form. The iDupont Nemoir & Company sold these materials under the trade name "Teflon (R) MP". The preparation of these copolymers is described in US Pat. No. 4,879,362 to Morgan. These copolymers are composed of a mixture of comonomers and comonomers selected from the group consisting of tetrafluoroethylene, and hexafluoropropene, perfluoro (alkyl vinyl ether) {the alkyl group has 1-4 carbons}. Has a repeating unit.

The present polymerizable compositions may include additives such as molybdenum disulfide, glass fibers, carbon fibers, and carbonaceous fillers such as graphite in addition to zinc oxide and PTFE. The particular additive chosen will depend on the desired effect.

In certain applications, it has been found advantageous to coat zinc oxide particles before incorporation into the polymerizable composition. Suitable materials include coupling agents such as titanate-, silane-, zirconaluminate-, and alumina-type coupling agents, silylating agents, silanol-modified silicone oils, alkoxy-modified silicone oils, and SiH-modified silicone oils. Can be mentioned. The coating material is generally used at less than 2% by weight, preferably from about 0.2 to about 1% by weight, based on the weight of zinc oxide.

The invention is further illustrated by the following examples (parts and percentages by weight unless otherwise indicated). Abrasion specimens were prepared by machining the test blocks of the compositions described in the Examples. The test block was machined such that the 6.35 mm (0.25 in) wide contact surface of the wear / friction test block had a curvature that conformed to the outer periphery of a 35 mm (1.38 in) diameter x 8.74 mm (0.34 in) wide metal mating ring. The blocks were oven dried and left on the dryer until testing.

Wear tests were performed using the "Falex NO.1 Ring and Block Wear and Friction Tester". The facility is described in ASTM test method D2714. After the survey, the dry block was mounted on a rotating metal ring and the selected test pressure was added thereto. The rotational speed of the ring was set to the desired speed. No gamma agent was used between mating surfaces. The ring was "SAE 4620 Steel, Rc 58-63, 6-12 RMS". New rings were used for each test. The test time was 24 hours unless the friction and wear were so severe that the test was terminated quickly. The friction force was recorded continuously. At the end of the test time, the blocks were unmounted, surveyed, and the degree of wear was calculated according to the formula:

Wear volume (cc / hr) = weight loss (g) / {material density (g / cc) x test duration (hr)}.

PV (pressure x velocity) limit tests were performed using the same “Falex No. 1 Ring and Block Wear and Friction Tester”. In this test, wear blocks and rings began to be treated at constant PV. At 10-20 minute intervals, PV was increased in increments by increasing the speed up to 2.67 mps (525 fpm) and then increasing the load until failure. Breakage was defined as a fast and uncontrollable increase in friction. Low wear volumes and low or narrow range coefficients of friction are desirable. PV limits are an indicator of the range of functionality for certain formulations. It is preferable that this value is large. Wear volume and coefficient of friction correlate with the dispersion uniformity of zinc oxide and PTFE in the polymer matrix.

Tensile properties were measured according to ASTM D638 and flexibility was measured according to ASTM D-790.

EXAMPLES Scanning electron microscopy / energy dispersion X-ray (SEM / EDX) analysis was used to determine the PTFF dispersion of a sample. This analysis provides information on the form and composition of the sample from the surface of the sample. Using a commercially available microscope and X-ray analyzer, the sample was placed in a vacuum chamber and rasterized the first electron beam across the surface. An image is obtained by electron reflection. Elemental information is obtained by X-ray emission, which characterizes each element in terms of energy. Each element is mapped by limiting detection to the desired energy level. Subsequently, whenever an X-ray of that energy is detected, the analyzer displays a bright dot at the grid position. As the first beam is rasterized across the sample surface, a map of x-ray light sources representing the corresponding elements is generated. The signal obtained by passing through the sample surface several times can be averaged to improve the resolution of the element map.

<Example 1>

56 parts of liquid crystalline polyester (DuPont Zenite® 6000) and 24 parts of polyimide resin (present as polyamic acid as its precursor) made from pyromellitic dianhydride and 4,4'-oxydianiline Zinc oxide additive (Matsushita's WZ-511 powder) and PTFE (DuPont Teflon® MP-1600 micropowder) having a starting average particle size of 2.1 μm were blended with the amounts listed in the following table to obtain the required formulation. This formulation was carried out using a 30 mm twin screw extruder with a barrel set at 290 ° C. and a die at 335 ° C. Quenching was performed using a water sprayer. The strands were cut into pellets using a standard rotary blade cutter. Pellets were molded into a standard 6.4 mm thick ASTM (D638) tensile test bar using a 170 g capacity, 145 ton clamping injection molding machine. The profiles were as follows: back temperature 313 ° C., center temperature 334 ° C., front temperature 335 ° C. and nozzle temperature 332 ° C .; Rise time 1 second, injection time 20 seconds, hold time 20 seconds, injection pressure 3.4 MPa, ram speed high speed, screw speed 107 rpm and rear pressure minimum.

The samples were machined into test specimens. Abrasion tests were performed at PV of 1.75 MPa-m / s (1.28 MPa, 1,36 m / s).

Sample number PTFE (part) ZnO (part) Wear volume (cc x 10 ^-4 / hr) Friction coefficient (Comparative Example) I 20 0 39.3 0.11-0.38 Comparative Example II 10 10 2.0 0.25-0.40

<Example 2>

56 parts of liquid crystalline polyester (DuPont Zenite® 7000) and 24 parts of polyimide resin (present as its precursor polyamic acid) made from pyromellitic dianhydride and 4,4'-oxydianiline Zinc oxide additive (Matsushita's WZ-511 powder) and PTFE (DuPont Teflon® MP-1600 micropowder) having a starting average particle size of 2.1 μm were blended with the amounts listed in the following table to obtain the required formulation. This formulation was carried out using a 30 mm twin screw extruder with a barrel set at 320 ° C. and a die at 335 ° C. Quenching was performed using a water sprayer. The strands were cut into pellets using a standard rotary blade cutter. Pellets were molded into a standard 6.4 mm thick ASTM (D638) tensile test bar using a 170 g capacity, 145 ton clamping injection molding machine. The profiles were as follows: back temperature 313 ° C., center temperature 334 ° C., front temperature 335 ° C. and nozzle temperature 332 ° C .; Rise time 1 second, injection time 20 seconds, hold time 20 seconds, injection pressure 3.4 MPa, ram speed high speed, screw speed 107 rpm and rear pressure minimum.

The samples were machined into test specimens. Abrasion tests were performed at PV of 1.75 MPa-m / s (1.28 MPa, 1,36 m / s).

Sample number PTFE (part) ZnO (part) Wear volume (cc x 10 ^-4 / hr) Friction coefficient Comparative Example III 20 0 9.9 0.22-0.26 (Comparative Example) IV 10 10 2.8 0.09-0.17

<Example 3>

The same sample preparation method as used in Example 2 was used except that the polyimide resin prepared from pyromellitic dianhydride and 4,4'-oxydianiline was each of the compounds listed in the table below.

Sample number LCP (part) Polyimide (part) PTFE (part) ZnO (part) PV limit (MPA-m / s) Abrasion ^* Volume (cc x 10 ^-4 / hr) Friction coefficient VI 63 27 10 0 4.6 15.2 0.26-0.40 VII 53 27 15 5 6.8 1.2 0.21-0.27 VIII 53 27 10 10 5.7 4.2 0.25-0.33 IX 53 27 5 15 - 5.0 0.23-0.32

By the SEM / EDX analysis, the PTFE dispersion of the obtained samples Samples VI and VIII was analyzed. The fluorine map of sample VI is shown in FIG. Here, a number of dense regions with fluorine enriched (ie low dispersion) appear. This is in contrast to sample VIII shown in FIG. 2 with fluorine uniformly dispersed. The wear volume of Sample VI was greater than three times that of Sample VIII, and the friction coefficient range was nearly twice that of Sample VIII.

<Example 4>

Samples were prepared as in Example 1.

Sample number PTFE (part) ZnO (part) Wear volume (cc x 10 ^-4 / hr) Coefficient of friction X 20 0 41.5 0.20-0.32 XI 10 10 7.2 0.20-0.33 XII 0 20 104.9 0.26-0.48

<Example 5>

Samples were prepared by the method of Example 2 using 280 parts of liquid crystalline polymer and 120 parts of polyimide in addition to the materials listed in the table below.

Sample number PTFE (part) ZnO (part) PV-limit (MPa-m / s) Mah volume (cc x 10 ^-4 / hr) Friction coefficient XIII ^* 100 0 4.6 5.1 0.21-0.28 XIV 95 5 5.6 1.7 0.19-0.28 XV 25 75 5.6 5.4 0.25 XVI 5 95 - 14.0 ^** 0.28-0.41 * (Comparative) ** The sample was broken after 3 hours, not 24 hours after all other samples were tested.

<Example 6>

56 parts of "Zenite® 6000" and polyamic acid, except that the zinc oxide used was 503 R, commercially available from "Zinc Corporation of American", with a post-painting average particle size of 3.7 μm and no distinctive structure. Samples XVII, XVIII and XIX were prepared as in Example 1 using 24 parts. Sample XVIII used zinc oxide coated according to the following procedure. To a 5 L round bottom flask was added 2 L of distilled water and 500 g of zinc oxide with stirring. The dispersion was heated to 75 ° C and the pH adjusted to 8.7. To this dispersion was added 100 ml of a solution containing 40 ml of alumina and 60 ml of distilled water while maintaining the pH at 8.2 with 17.5% hydrochloric acid solution. The dispersion was then stirred for 30 minutes, filtered, washed with distilled water and placed in an oven at 110 ° C. until dry. Samples were adjusted to the required particle size.

Sample XIX used zinc oxide coated according to the following procedure. To a 5 L round bottom flask 3 L of distilled water and 500 g of zinc oxide were added with stirring. The dispersion was heated to 75 ° C and the pH was adjusted to 9.5 with 30% sodium hydroxide solution. 42.5 g of "Kasil" (Vinnings VSA-38) diluted to 100 ml with distilled water was added over 30 minutes while maintaining the pH at 9.5 with 17.5% HCl solution. The dispersion was stirred for 30 minutes. The pH was adjusted to 8.2 with 17.5% HCl solution while maintaining the pH at 8.2 with 17.5% hydrochloric acid solution and 40 ml of alumina was added for 30 minutes. The dispersion was stirred for 30 minutes, then filtered, washed with distilled water and placed in an oven at 110 ° C. until dry. Samples were adjusted to the required particle size. Sample XX was prepared according to Example 1 using 56 parts of "Zenite® 6000" and 24 parts of polyamic acid precursor. "WZ-511" zinc oxide powder was used as received from a supplier.

Sample number PTFE (part) ZnO (part) Paint type Wear volume (cc x 10 ^-4 / hr) Friction coefficient Tensile Strength at Break (MPa) Elongation (%) Flexible strength (MPa) Flexible Modulus (GPa) XVII 10 10 Unpainted 16.7 0.3-0.35 34.5 1.7 53.8 0.38 XVIII 10 10 Amorphous alumina 12.4 0.27-0.37 35.8 1.9 57.9 0.39 XIV 10 10 Alumina silica 13.6 0.29-0.35 43.4 2.2 70.3 0.39 XX 10 10 Organic matter 13.0 0.28-0.35 45.5 2.5 70.3 0.41

<Example 7>

Samples were prepared according to Example 1 without incorporation of polyimide. Wear tests were performed with PV of 0.34 MPa-m / s (3.4 MPa, 0.1 m / s).

Sample number LCP (part) PTFE (part) ZnO (part) PV limit (MPa-m / s) Wear volume (cc x 10 ^-4 / hr) Friction coefficient XXI 70 15 15 3.42 6.5 0.12-0.13 XXII ^* 70 30 0 0.7 0.2 0.16-0.21 * (Comparative)

<Comparative Example 8>

56 parts of polyamide (DuPont Zytel® HTN), 10 parts of zinc oxide additive (Matsushita's WZ-511 powder) with a starting average particle size of 2.1 μm, PTFE (DuPont Teflon® MP-1600 micropowder) 10 Sample XXIII was prepared by blending 24 parts of a polyimide (present in its precursor polyamic acid) prepared from parts and pyromellitic dianhydride and 4,4'-oxydianiline in the amounts to obtain the percentages shown in the table below. This formulation was carried out using a 30 mm twin screw extruder with a barrel set at 320 ° C. and a die at 335 ° C. Quenching was performed using a water sprayer. The strands were cut into pellets using a standard rotary blade cutter. Pellets were molded into a standard 6.4 mm thick ASTM (D638) tensile test bar using a 170 g capacity, 145 ton clamping injection molding machine. The profiles were as follows: back temperature 315 ° C., center temperature 335 ° C., front temperature 335 ° C. and nozzle temperature 335 ° C .; Rise time 0.5 seconds, injection time 20 seconds, hold time 20 seconds, injection pressure 4.8 MPa, ram speed high speed, screw speed 120 rpm and rear pressure 0.34 MPa.

Sample XXIV used an imidized polyimide powder resin prepared from pyromellitic dianhydride and 4,4'-oxydianiline.

The samples were machined into test specimens. Abrasion tests were performed at PV of 1.75 MPa-m / s (1.28 MPa, 1,36 m / s).

Sample number PTFE (part) ZnO (part) Wear volume (cc x 10 ^-4 / hr) Friction coefficient XXIII 10 10 10.0 0.16-0.28 XXIV 10 10 8.1 0.20-0.27

<Example 9>

A sample was prepared as in Example 1 using 10 parts of zinc oxide relative to 10 parts of PTFE. The mixed resin was injection molded into a 1.5 mm thick x 50.8 mm diameter disc used as a Hysteresis Washer. The conditions used for this were as follows: barrel temperature 320 ° C, rear temperature 335 ° C, front temperature 335 ° C. Nozzle molding temperature of 100 ° C .; Cycle rise time 1 second, injection time 15 seconds, cooling time 20 seconds; Rear pressure 0.3 MPa, rise pressure 2.7 MPa, injection pressure 2.4 MPa; Ram speed high speed, screw speed 84 rpm. After 10,000 km of operation, the washer was operated in accordance with the requirements with little evidence of wear.

Claims (12)

(a) about 40 to about 93 weight percent of at least one thermoplastic polymer that is melt processable at temperatures below about 400 ° C., (b) about 1 to 19 weight percent of zinc oxide with an average particle size of less than about 3.7 μm, (c) about 1 to 38 weight percent of a fine powder tetrafluoroethylene polymer or copolymer having a molecular weight of about 80,000 to about 1,000,000 and an average particle size of about 1.5 to 150 μm, The tetrafluoroethylene powder and the zinc oxide particles are present in the composition in a weight ratio of about 95 parts of tetrafluoroethylene powder to about 5 parts of zinc oxide particles to about 10 parts of tetrafluoroethylene powder per 90 parts of zinc oxide particles, A polymerizable composition in which the tetrafluoroethylene powder is uniformly dispersed throughout the polymerizable composition. The composition of claim 1, wherein the thermoplastic polymer is a liquid crystalline polymer and the tetrafluoroethylene polymer or copolymer is nonfibrillable. The composition of claim 1 further comprising about 5 to 40 weight percent of (d) polyimide resin. The composition of claim 1 wherein said thermoplastic polymer is a polyamide. 2. The polyimide of claim 1, which is present as (d) a polyimide precursor resin prepared from at least one aromatic diamine and at least one aromatic dianhydride, wherein less than about 98% of the polymer units are converted to polyimide resins. The composition further comprises about 5 to 40% by weight. The composition of claim 1, wherein the zinc oxide particles are coated with a coupling agent on a surface thereof. The composition of claim 3, wherein the polyimide is present in an amount of 10 to 25% by weight, and at least 25% of the zinc oxide particles have a particle size of less than 2 μm. 3. The liquid crystalline polymer according to claim 2, wherein the liquid crystalline polymer consists essentially of (I) hydroquinone, (II) 4,4′-dihydroxyphenyl, (III) terephthalic acid, (IV) 2,6-naphthalene dicarboxylic acid and (V) consisting of repeating units derived from 4-hydroxybenzoic acid, the molar ratio of (I) :( II) is 65:35 to 40:60, and the molar ratio of (III) :( IV) to 85:15 50:50, the molar ratio of (I) :( II) to the sum of (III) :( IV) is substantially 1: 1, and (V) per 100 moles of (I) + (II) is from 200 to 600 Molar present compositions. The aromatic diol of claim 2, wherein said liquid crystalline polymer consists essentially of (I) 95-55 mol% t-butylhydroquinone and 5-45 mol% of at least one polyaromatic diol, (II) "para" or " Meta "oriented aromatic dicarboxylic acid or dicarboxylic acid component selected from 1,4-cyclohexane dicarboxylic acid or mixtures thereof, provided that up to 80 mol% of the dicarboxylic acid component comprises naphthalene dicarboxylic acid And (III) an aromatic hydroxycarboxylic acid component selected from 4- (4 "-hydroxyphenyl) benzoic acid or mixtures thereof, containing components (I) and (II) in the same chemical equivalent weight, A composition comprising component (III) from about 20 to 60 mole percent, based on the total moles of (I) + (II) + (III). A molded article made from the composition of claim 1 used as a wear and support material. A molded article made from the composition of claim 2 used as a wear and support material. A molded article made from the composition of claim 3 used as a wear and support material.